1. Field of the Invention
The present invention relates to a method and a system for assessing the relative pose of an implant and a bone of a creature.
2. Background
For the assessment of the relative pose of an implant and a bone of a creature usually X-ray images are used, in particular in a surgery environment when bone fragments have to be fixed in the correct pose. Usually, so-called C-arm systems are used which combine an X-ray source and a X-ray detector on a mobile cart having the form of the letter “C” allowing to rotate the X-ray source in the range of about at least 180° around a human patient or an animal. Nevertheless, since the C-arm device is mobile device, the image information contributes to a first control of what has been done by the surgeon but lacks precise information.
With the availability of X-ray computer tomography imaging (CT) and, of course, other image generating devices, like ultra-sound or magnetic resonance imaging (MRI), the possible shortcomings of the 2D C-arm information can be mitigated by post-operative CT scans for a precise assessment of the surgery results. Unfortunately, this means that patients have to undertake a re-surgery in order to reposition a bone fragment and/or the respective implant in case of mal-alignment or miss-placement of the implant. This problem has been addressed by the design of mobile CT scan machines which can be also used already in the operation room or mobile C-arms with 3D scan capabilities. These mobile CT scan machines do have clinical workflow limitations. Therefore, a real demand exists for providing 3D information in 2D X-ray images in the operation room.
To solve this problem, diverse software products exist which are designed to link information between medical image viewers (U.S. Pat. No. 7,489,810). This US patent discloses a method and a system for linking position (pose) information between two-dimensional (2D) and three-dimensional (3D) software applications for viewing diagnostic medical images. The position location information is integrated between 2D and 3D viewing paradigms. This integration provides directional communication between the 2D and 3D viewing paradigm systems. The 3D cursor allows for immediate synchronized navigation through different image sets such 3D magnetic resonance images and 2D images while they are being simultaneously viewed on the two different viewing applications. Further, diverse software products exist being designed to improve the X-ray diagnosis in breast cancer and lungs cancer computer assisted detection (CAD). However, there is still a demand for a computer assisted 3D detection of the implant position (pose estimation) during a surgery.